# Hacking Tube

## ASIS CTF 2015 Quals -- grids

Category: Programming
Points: 300

In each stage send the maximun size of area that can be covered by given points as a vertex of polygon in 2D.
nc 217.218.48.84 12433
mirror 1 : nc 217.218.48.84 12432
mirror 2 : nc 217.218.48.84 12434
mirror 2 : nc 217.218.48.84 12429

Took me a while to figure out that the challenge was asking us to solve a Convex Hull problem.

The service provide us a list of vertices (2-D). We'll have to find the vertices that can form a convex hull and calculate its size of area. Fortunately, there's a python library call scipy, which can be used to find a convex hull by giving an array of vertices. After we find all the vertices, we can simply calculate the size of area by using determinant.

After solving 99 problems, we got the flag: ASIS{f3a8369f4194c5e44c03e5fcefb8ddf6}